One type of apparatus which provides for both the dumping and spreading of material, such as sand, salt, gravel, asphalt and the like, onto a surface is commonly referred to as a combination body. Combination bodies are so named because they provide, in combination, both dumping and spreading functions. Examples of combination bodies are shown and described in U.S. Pat. Nos. 5,400,974; 5,772,389; and 6,394,735.
In general, combination bodies are pivotally mounted to the chassis of a vehicle, typically a truck chassis. Although the bodies can be mounted so as to pivot in one or more directions, the most common mounting arrangement provides a hinge mechanism on the rear end of the body and a hydraulic cylinder on the front of the body, wherein movement of the cylinder causes the body to pivot about the rear hinge mechanism. This pivoting movement provides the bodies with the ability to dump material from the rear of the bodies.
A tailgate can be provided that covers the rear of the body. The tailgate can pivot into an open position when it is desired to utilize the dumping functionality of the body.
A conventional combination body can further include a conveyor system that transports material residing within the body out of the body and into one or more spreaders mounted on the exterior of the vehicle. The tailgate can include at least one opening therethrough to provide a means by which the material, upon transport by the endless conveyor, can be expelled from the rear of the body. Upon being expelled from the body through the tailgate opening, the material can be directed into a rear spreader at least in part by a cover or tail gate chute affixed to the tailgate.
While existing combination dump and spreader bodies provide many desirable features and advantages, there remain certain problems with these combination bodies. For example, a combination body configured to be used with a tailgate typically has an open rear end, which reduces the overall structural integrity of the body. Providing a conveyor that runs lengthwise down the center of the body further reduces the strength of the body across the body width at the rear end because the middle portion of the main reinforcement of the rear base of the body is removed to make room for the conveyor system. This is especially a problem in a truck body having an essentially flat floor. The reduced strength of the body can lead to the body sagging at its rear end.
In addition, a vehicle with a conventional combination body is often difficult to convert from a “snow truck” to a “general purpose truck.” A truck body that can easily be used for both winter and summer applications would be very desirable to help limit the number of vehicles a municipality might need to own and maintain. Furthermore, the ability to rapidly convert a vehicle from a “snow truck” configuration to a “general purpose truck” configuration can increase the municipality's workforce productivity during the winters months because many winters include days having weather that allows for, or even requires, work to be done without the interference of the “snow truck” equipment.
Another issue with conventional combination bodies is that they can be very difficult to disassemble. Certain parts of combination bodies, such as the conveying system, often require maintenance. However, limited access can make it difficult to disassemble certain parts of the combination body to perform such maintenance. Often those performing maintenance on the conveying system must intentionally destroy certain parts of the combination body, especially conveyor shafts and the surrounding area, that otherwise are functioning normally to access the parts of the combination body requiring service. This practice is inefficient and wasteful.
In view of the foregoing, there exists various needs in the art. One such need is for a combination body with increased strength which still includes a pivotally mounted tailgate and a conveyor system. A further need exists for a combination body that is readily convertible between a snow truck configuration and a general purpose configuration. An additional need is for a combination body having a conveyor shaft assembly that can be easily and reliably disassembled and reassembled.